An assembled battery pack is known, that combines a plurality of small battery packs by passing a through-bolt in a hole provided in the frame of a battery pack spacer for flat batteries. (for example, see Japanese Patent Application Publication No. JP 2009-272234 A). In Japanese Patent Application Publication No. JP 2009-272234 A, at the increase of the number of stacking or laminations, when the small battery packs are deviated even slightly, a problem arises that the through-bolt is difficult to be inserted into the hole and thus the assembly workability will be decreased.